Migrate add_missing_match_arms assist, because edit_in_place uses ted

[A4-Tacks]

• And fix indentations

Example

fn main() {
    match None$0 {
        None => {
            foo(
                "foo",
                "bar",
            );
        }
    }
}

Before this PR:

fn main() {
    match None {
        None => {
                foo(
                    "foo",
                    "bar",
                );
            }
        Some(${1:_}) => ${2:todo!()},$0
    }
}

After this PR:

fn main() {
    match None {
        None => {
            foo(
                "foo",
                "bar",
            );
        }
        Some(${1:_}) => ${2:todo!()},$0
    }
}